Field
Embodiments of the present disclosure generally relate to sucker rod pumps, and more specifically, to coatings for sucker rod pump plungers and barrels.
Description of the Related Art
Beam pumping, or the sucker-rod lift method, is the oldest and most widely used type of artificial lift for most wells. A sucker-rod pumping system is made up of several components, including a surface-pumping unit and an underground pump, e.g., a rod pump, coupled to one another by a sucker rod. The inside surface finish and inside diameter of the sucker rod pump barrel affect the operation of the rod pump due to the small clearances that exist between the pump barrel and the plunger (e.g., about 0.002 inches per side). If the clearances are too large, efficiency of the pump is reduced. In addition to large clearances, scoring from sand or other particulate can also cause the efficiency of the sucker rod pump to drop. Scoring can be exacerbated in instances of reduced clearance.
To reduce scoring of the rod pump, conventional approaches have utilized a chrome coating on components of the rod pump. Chrome, however, is subject to “microcracking” which renders the chrome porous. FIG. 1 illustrates a conventional chrome coating 190 disposed on a rod pump component 191. The chrome coating has a microcrack 192 formed therein. Within corrosive wells, fluid can penetrate the microcrack 192 of the chrome 190, resulting in corrosion 193 of the underlying steel substrate, such as a rod pump component 160. Corrosion of the underlying steel substrate significantly decreases the useful life of the rod pump.
As an alternative to steel, brass substrates have been proposed. However, the chrome layer is more susceptible to surface deformation when placed over a softer brass substrate.
Therefore, there is a need for a rod pump with reduced corrosion and scoring characteristics.